import { Mutex } from "app-mutext";

new Mutex("4cdb4d66-2d29-47fd-adaa-b2e8e72a6803", (status) => {
    switch (status) {
        case "CLEAR": break; // its ok
        case "PID_DEAD": // warning
            console.log("last time app ran, a critical error occurred.")
            break;
        case "CONFLICT":
            console.log("[ERR] app already running.");
            process.exit(-1);
            break;
    }
});


/* ... */

your code...

/**
 * Mutext status type
 * @argument ERR_NOT_INIT - Mutex not been initiated
 * @argument CLEAR        - Mutex status - success, you can run application
 * @argument CONFLICT     - Mutex detected runned this application
 * @argument PID_DEAD     - Mutex was noticed that the application died
 */